Thread feeding device for inserted weft knitting machines

ABSTRACT

Elastic yarns are fed to knitting machines by measuring predetermined amounts of the elastic thread or yarn, which otherwise would be non-uniform in length or degree of stretch because of the high and not always uniform elasticity of the yarn. There are two distinct variants. Both variants include feeding out from yarn packages by driving the yarn package by friction on its surface. The first variant is for a weft knitting machine, such as a circular knitting machine, and in it a package of elastic yarn is moved along the needle line with a drive roller in contact with its surface, which roller turns as the package moves. The speed of the roller determines length of the elastic yarn paid out. Knitting is either by a non-elastic yarn which knits around the paid-out elastic yarn in the case of single knit machines, or in the case of double knit machines the paid-out elastic yarn may be sandwiched between the two layers of the double knit. The second variant deals with a multiple-package filling-thread-feeding device for warp knitting machines of the so-called &#39;&#39;&#39;&#39;carousel&#39;&#39;&#39;&#39; type in which thread from a plurality of packages, which are moved around by an endless chain, is fed to transfer chains provided with pins which carry the filling or weft threads to the knitting line, the motion of the packages stringing successive filling thread lengths from the pins on one chain to the pins on the other, and which provides for intermittent tensioning devices for the thread, for example spring-pressed discs, the tension being applied to the thread as it is clamped by the pin on one chain, then the tension releases, for example by a cam, until just before reaching the corresponding pin on the second chain and the tension is reapplied. The threading device is modified for feeding elastic yarn preferably by providing the yarn package, having a hollow core, with means for preventing rotation of the core for a portion of the travel of each package from carrier chain to carrier chain, the means preferably which apply a brake to the inside of the hollow core and cam which raises each package during a portion of the stringing from chain to chain which releases the braking means and permits rotation of the cores. The cams are of suitable length so that the elastic yarn is paid out a desired amount. The packages are moved along the cam and are turned thereby. In the unbraked portion of the travel a predetermined length of elastic yarn is paid out. Braking permits a predetermined stretch of the yarn. Instead of a large hollow core, packages may be on spindles to which intermittently brakes may be applied by any suitable means.

United States Patent [191 Walford Oct. 14, 1975 THREAD FEEDING DEVICEFOR INSERTED wEFr KNITTING MACHINES [75] Inventor: Richard L. Walford,Bloomfield,

[73] Assignee: J. P. Stevens & Co., Inc., New York,

[22] Filed: July 1, 1974 [21] Appl. No.: 484,650

Primary ExaminerRonald Feldbaum Attorney, Agent, or FirmRobert AmesNorton; Michael T. Frimer; Saul Leitner [5 7] ABSTRACT Elastic yarns arefed to knitting machines by measuring predetermined amounts of theelastic thread or yarn, which otherwise would be non-uniform in lengthor degree of stretch because of the high and not a]- ways uniformelasticity of the yarn. There are two distinct variants. Both variantsinclude feeding out from yarn packages by driving the yarn package byfriction on its surface. The first variant is for a weft knittingmachine, such as a circular knitting machine, and in it a package ofelastic yarn is moved along the needle line with a drive roller incontact with itssurface, which roller turns as the package moves. Thespeed of the roller determines length of the elastic yarn paid out.Knitting is either by a non-elastic yarn which knits around the paid-outelastic yarn in the case of single knit machines, or in the case ofdouble knit machines the paid-out elastic yarn may be sandwiched betweenthe two layers of the double knit. The second variant deals with amultiple-package filling-thread-feeding device for warp knittingmachines of the so-called carousel type in which thread from a pluralityof packages, which are moved around by an endless chain, is fed totransfer chains provided with pins which carry the filling or weftthreads to the knitting line, the motion of the packages stringingsuccessive filling thread lengths from the pins on one chain to the pinson the other, and which provides for intermittent tensioning devices forthe thread, for example springpressed discs, the tension being appliedto the thread as it is clamped by the pin on one chain, then the tensionreleases, for example by a cam, until just before reaching thecorresponding pin on the second chain and the tension is reapplied. Thethreading device is modified for feeding elastic yarn preferably byproviding the yarn package, having a hollow core, with means forpreventing rotation of the core for a portion of the travel of eachpackage from carrier chain to carrier chain, the means preferably whichapply a brake to the inside of the hollow core and cam which raises eachpackage during a portion of the stringing from chain to chain whichreleases the braking means and permits rotation of the cores. The camsare of suitable length so that the elastic yarn is paid out a desiredamount. The packages are moved along the cam and are turned thereby. Inthe unbraked portion of the travel a predetermined length of elasticyarn is paid out. Braking permits a predetermined stretch of the yarn.Instead of a large hollow core, packages may be on spindles to whichintermittently brakes may be applied by any suitable means.

5 Claims, 11 Drawing Figures US. Patent oct.14,1975 sheetlom 3,911,698

Sheet 2 of 4 US. Patent Oct. 14, 1975 m 'lll 25 \H l W Illn HUN US.Patent Oct. 14, 1975 Sheet 3 of4 3,911,698

US. Patent Oct. 14, 1975 Sheet 4 of4 3,911,698

THREAD FEEDING DEVICE FOR INSERTED WEFT KNITTING MACHINES BACKGROUND OFTHE INVENTION Knitting machines and preferably warp knitting machineswith inserted weft or filling threads at the knitting line have achievedgreat commercial success because of the enormous speed possible on theknitting machine as compared with an ordinary loom for weaving. The feedof wefts to a warp knitting machine presented a serious problem becauseof the great speed of the machine and hence the speed with which threadis taken from a package. The thread or yarn which constitutes the weftis carried to the knitting line, as is conventional in warp knittingmachines, bya pair of chains with pins or clips. The thread as it passesthe first chain is grasped by an open clip which then closes, normallyunder spring pressure, and the thread then strings across to the secondchain, where the clipping of the pins is repeated, and normally aftergrasping the thread it is cut, leaving an end. If a single package isused, the thread is fed at speeds reaching 100 miles per hour and more,if the machine is to be used at the maximum speed that the otherelements would permit.

A few years ago an important advance was made, which is described in theCarman US. Pat. No. 3,364,701. In this patent a large number, forexample 12, 24 or more, of packages of weft thread were moved around onan auxiliary chain and strung from one conventional carrier chain toanother, which chains, as mentioned above, carried the length of weftthread to the knitting line. Speed of thread feed was greatly reduced,and different threads, for example different colors, were possible toproduce special patterns where desired. Because of the moving around ofthe package on their auxiliary chain this device is known in theindustry as the carousel type of feeding device, and this name will beused in much of the following specification to save awkward language.

Some problems arose because the carousel machines had to carry atensioning device along with each package because unless the yarn isunder suitable tension it will not be strung out between the carrierchains uniformly without sagging. Tension is actually only required whenthe thread is first attached to a pin on the first carrier chain andagain as it approaches the pin on the second chain. However, whentension is maintained throughout the whole stringing there isconsiderable strain on the thread, and this raises various problems,such as lint formation and the like. Also, the friction may limit thespeed of feeding, particularly with relatively fragile threads or yarns.

An improvement on the Carman carousel is described and claimed in theJones U.S. Pat. No. 3,636,731, Jan. 25, 1972. In this improved machinetension to the yarn as it is strung from carrier chain to carrier chainis applied only for short periods adjacent each of the chains and therest of the stringing is tension free. For example, this is effected bya cam on the frame of the machine which releases tension, for example ifa preferred springpressed disc tension means is used, by raising a rodwith a wedge-shaped end that separates the disc against spring pressure.The Jones intermittent tensioning represented a marked improvement whichpermitted feeding at maximum speed and minimizing strain on yarn, lintformation, and the like.

Although the Jones device represented an important practical improvementon the original Carman carousel, it was still only useful with yarnswhich did not stretch readily. Inserted-weft warp-knit fabrics are oftendesirable with elastic weft yarns, which can produce one-way stretchfabrics if only the weft is elastic or two-way stretch if the warp yarnswhich are actually knit are also elastic. Such fabrics were notpractical on the Jones device, and this left elastic knit fabric toother less efficient and complex feeding configurations. One variant ofthe present invention deals with an improvement to the Jones knittingmachine feed, which improvement permits the use of elastic wefts.

SUMMARY OF THE INVENTION The present invention has two variants which,while they have a common feature, are very different in theirconstruction. The first variant is for a weft knitting machine of thesingle or double knit type, such as a circular knitting machine, whichwill be the form later on first specifically described, although it willbe pointed out that the same features may be used in a weft knittingmachine in which the needles are in a straight line and the feed of theweft is first in one direction across the needles and then reversedagain across them in the opposite direction and so on. In the variantapplying to weft knitting machines, a package of elastic yarn, or ifmultiple yarns are needed more than one package, is moved along theneedles, for example around the periphery of a circular knittingmachine. The knitting takes place with non-elastic yarns and may beeither single or double, but, as will be pointed out below, the elasticweft yarn is laid out by the same means.

As the yarn package or packages move along the needles the package isturned by friction of a driving roller or face driven, which causes itto pay out the elastic weft yarn at a predetermined rate, i.e., apredetermined length of elastic yarn for each revolution of a circularknitting machine or movement of the package across the needles in thecase of a straight knitting machine. The paying out of the yarn is notunder tension because the surface of the package turns with theperipheral speed determined by the diameter of the driving roller.

It is often desired to have an accurate predetermined tension on theelastic yarn. This has been impractical in the past with extremelycomplicated and expensive mechanisms. In the variant of the presentinvention dealing with weft knitting machines, an exact predeterminedtension may be imparted by having the roller pay out elastic yarn at aslower rate than the movement of the yarn package. While the amount ofyarn paid out for a particular rotation of the drive roller is constant,if the roller pays out elastic yarn at a slower rate than the movementof the yarn package along the needles, an exactly determined stretchresults. In many weft knitting machines where it is desired to have acertain stretch in the final fabric it is usually essential that thisamount of stretch be uniform. If it is attempted to produce a stretch inthe fabric by moving elastic yarn through tension devices, uniformity isimpossible because there is no such thing as an elastic yarn ofabsolutely uniform stretchability throughout its whole length. Thepresent invention produces the completely uniform desired degree ofstretch with the simplest of mechanisms, which permit maximum speed ofthe knitting machine. This solves an important element of the stretchproblem for high speed use because if tension is used and the yarn ispulled through the tension de vice very rapidly, the friction is highand variations in stretchability of the yarn become more serious. It hasbeen stated above that very elaborate mechanisms would be required toprovide uniform stretch. This is particularly true with elastic yarnssuch as Spandex, which is uncovered, a form of yarn which is desired inmany knitted fabrics. Somewhat simpler operation has been effected withcovered elastic yarns, where there is a covering of unelastic textilethread. This limits the amount of stretch irrespective of thestretchability of the elastic yarn itself; and therefore even if thereare some differences in stretchability as the elastic yarn is fed to theknitting machine, it is practical to use covered elastic yarns. Thepresent invention is useful with such yarns but does not have as greatan advantage as the reduction in costs available is less, and of coursethere are great savings where uncovered elastic yarns are used in thefabrics where they are desired. This is applicable to many fabrics, someof which have not been produced with uncovered elastic yarns because ofthe excessive costs, and now this is feasible.

It has been stated above that the present invention in its variant forweft knitting machines is applicable to single knit or double knit. Theactual mechanical situation in the fabric is, however, a littledifferent. In the case of single knits, the non-elastic textile yarnwhich is knit is knit around the elastic weft. In the case of doubleknit fabrics, it is usually preferable to adjust the machine so that theelastic yam at constant, predeter mined stretch is sandwiched betweenthe two layers of the double knit fabric. The operation of the weftknitting variant of the present invention performs essentially the samefunction. It should be noted that in the weft knitting machinepredetermined stretch of elastic yarn is produced with only a singlemechanical organi zation, that is to say, the driving of the yarn by adrive roller and the movement of the whole package. It should also benoted that as a package becomes used up some means must be provided tokeep the roller in contact with the surface. This is extremely simpleand can be affected by spring pressing the roller against the package.This involves relative movement of the package and the roller and it istheoretically immaterial which one is moved. However, as the roller hasto be driven, simpler mechanisms are provided if the movement is of theyarn package rather than of the roller.

The second variant of the present invention deals with warp knittingmachines. This is at present commercially the more important one. Hereseveral additional functions are performed over the weft knittingmachine, and the present invention finds its greatest commercialadvantage in the warp knitting field. While, as will appear from thedescription below, both variants involve friction surface or face driventurning of the elastic yarn package, their mechanisms are verydifferent; and therefore, as will be seen, the two variants areindependently claimed in different sets of claims.

The preferred warp knitting variant of the present invention preferablyuses a carousel type of warp knitting machine with the improvement ofthe Jones patent referred to above. The invention will be described inconjunction with a modified Jones machine in which the yarn packages aremoved around by a chain on spindles, preferably extending horizontallyas is described in the Jones machine rather than vertically as in theoriginal Carman carousel, but the yarn packages are not of conventionalconstruction, i.e., they are not packages which are mounted on spindlesattached to the package carrier chains. If it is attempted to use thesame design of standard yarn package that is illustrated in the Jonespatent with elastic yarn packages, the yarn will stretch varying amountsbecause it is impossible to adjust tension so that with elastic yarn nostretch results or that a stretch of a predetermined amount results.Therefore, the Jones machine has not proven useful for feeding insertedwefts of elastic yarn or thread.

In the present invention there is provided one or more cams on the frameof the knitting machine, in addition to the cams which activate anddeactivate the tension devices. These cams contact the yarn packages asthey move past, causing the packages to turn and pay off a length ofelastic yarn equal to the length of the cam. It is usually desirable tohave more than one cam so that the paid-out lengths of elastic yarn arenot too long. This is of importance as many warp knitting machines arevery wide, for example up to inches. As a portion of the yarn is paidout, when it leaves the cam it is desirable to stop the rotation of thepackage for predetermined distances. This performs two functions. First,it catches up with any excessive slack produced by overshooting of theyarn paid off from the spinning packages and, more importantly, canimpart a certain, exactly predetermined degree of stretch to the weftlaid across from carrier chain to carrier chain of the knitting machine.While it is possible with a single cam surface to feed elastic yarn forthe whole length of the weft in a completely relaxed form, it is oftenpreferred to have this weft under a certain predetermined tension, andthis is effected by braking the rotation of the package at predeterminedpoints and for predetermined distances. This is best accomplished byhaving more than one cam.

The present invention in its broadest aspect contemplates any means ofintermittent braking of the spinning packages at precisely predeterminedpoints and for a precisely predetermined distance of package movement.This can be effected in many ways, for example by separate cams,solenoid operation, and the like. However, in a preferred embodiment thebraking mechanism can be carried by each package itself. These brakingmechanisms can be deactivated by the raising of the package as it mountsthe entrance ramp of each cam and activated as it is lowered when itleaves the exit ramp. This is very simple, very economical of equipment,and is preferred. The description below, both in general summary andstill further below in the description of preferred embodiments, will bein terms of such a modification.

In the preferred modification the package is of quite different designwith a relatively large cross-section hollow core on which the yarn iswound. Inside this hollow core are means, preferably a spring attachedto the yarn package carrying spindle and another shaft carrying aprojecting brake shoe. When the packages are in their lowered position,that is to say not riding on a cam profile, the inner core cannot turnabout the spindle and elastic yarn is strung in a stretched state and/orslack taken up. Then when each package encounters the cam or cams and israised, this turns the shaft carry ing the brake shoe against springpressure and allows the package to roll freely on the cam and to unwindits elastic yarn under substantially no pressure because, of

course, the cams are arranged so that the packages are raised when theintermittent tensioning means of the Jones machine is also released. Bythe choice of a particular length of cam or cams the elastic yarn can bestrung from carrier into carrier chain at an accurately predeterminedtension. Ordinarily when elastic fabrics are to be knit, the elasticweft is under some tension but the tension should be small so that thefabric does not pucker. The present invention permits stringing theelastic yarn at any desired very low tension, and this can be adjustedby the length of the package raising cam or cams and, therefore, permitsstringing elastic yarn under the exact tension desired.

As has been described in the Jones patent, the intermittent tensioningcan be effected by a number of .means. However, in the present casethere will be described only the tensioning means actually set forth inthe Jones patent because the particular tensioning means forms no partof the present invention. In referring to tensioning means it is, ofcourse, not referring to the braking and relaxation of the elastic yarnpackages but rather the spring-pressed discs with wedgeshaped rods shownin the Jones patent. The intermittent tensioning means of the Jonespatent, which are used only for extremely short periods as the yarn isclamped onto the pins of each carrying chain, are in addition to thebraking of the turning packages referred to above.

In the preferred variant of the present invention, i.e., with warpknitting machines, it is an advantage of the present invention that theknitting machine described in the Jones patent need not be extensivelyrebuilt since the modified yarn packages with hollow cores move over theframe of the knitting machine shown in the Jones patent and theadditional cam or cams are readily attachable thereto and preferablyshould be detachably mounted, for example, by machine bolts, so thatcams of various lengths can be provided depending on the particularelastic yarn which is to be fed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of the weft feedtransport and carousel in semi-diagrammatic form and illustrates themodification to the standard Jones machine;

FIG. 2 is a section along the line 22 of FIG. 1;

FIG. 3 is a section at right angles to FIG. 2;

FIG. 4 is a section along the line 4-4 of FIG. 2;

FIG. 5 is similar to FIG. 4 but illustrates a retracted cam follower;

FIG. 6 is a section through a yarn package, 91, showing the brake showin braking position;

FIG. 7 is a similar cross-section of package 9J with the package raisedby the brake show releasing cam;

FIG. 8 is a diagrammatic illustration of a shaft and elements in FIGS. 6and 7, the inner core of the yarn package being omitted for clarity;

FIG. 9 is a diagrammatic view of a variant for feeding elastic yarn in aweft knitting machine, and

FIGS. 10 and 11 are sections along the lines 10-10 and 11-11 of FIGS.-9to 11 show only a part of the machine.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The variant of FIGS. 1 to 8,which deals with the application of the present invention to a warpknitting machine will first be described. FIG. 1 is a plan viewmodification made by the present invention. Being a plan view, thepackages on the carousel are not all in one plane as the two weftcarrier chains 1L and IR extend up at an angle from the plane of thecarousel itself, these chains carry conventional clamping pins 2, whichare opened on chain 1R as it is approached by the yarn, as will bedescribed, and of course opened when the weft has been carried to theknitting line. The drawing does not extend this far and the knittingline is not shown as it is not changed by the present invention. Theopening and closing of the clamping pins is by conventional cam means onthe sprockets for the chains. It is not shown as it is not changed bythe present invention any more than it was in the Jones machine. Theoperation is known and is illustrated in FIG. 5 of the above mentionedCarman patent, to which reference is hereby made for an illustration ofthis known mechanism. In other words, this portion of FIG. 1 is inpurely diagrammatic form.

As in the Jones patent, this modified carousel portion is built on aframe 7 provided with an endless carrier in the form of two chains, awider chain 5 on which the yarn packages are carried and a narrowerchain 8 on which the tensioning devices for each package are carried. Ascan be seen from FIG. 1, the packages, which are numbered 9A to 9K, arehorizontal; in other words in a modified carousel rather than the formin the original carousel patent mentioned above, in which the packagesextend vertically. The Jones machine can be operated with verticalpackages but the present invention, while not inoperative with verticalpackages, is much less convenient and the horizontal packagemodification illustrated in the drawings and here described constitutesa definitely preferred form. The drive for the chains 1L and IR and forthe chains 5 and 8 is taken from the main drive for the knittingmachine, as diagrammatically indicated at 6. The mechanical connectionsare not specifically illustrated as they would only confuse the drawingsand are not changed by the present invention. Similarly, only the elevenpackages which can be seen by looking down on the carousel are shown,but of course the chains 5 and 8 are endless.

Each package has its own tensioning device, labelled 10A to 10K, thelettering corresponding with the packages. Yarn from the packages isnumbered 11A to 1 1K and runs from each package to its tensioningdevice. Before describing the construction of the tensioning device andtheir auxiliary equipment, which are the preferred form of the Jonespatent and also constitute the preferred but not limiting form for thepresent invention, the general operation will be described.

The chains 5 and 8 move from right to left, as can be seen by the arrowaround the shaft from the drive 6, and the chains 1L and IR movediagonally up. All the chains are, of course, endless and return, but inFIG. 1 the return is not shown. Packages 9A and 9K are turning around anend sprocket, (not shown), of chain 5. The mounting of the package onthe chain includes a bracket 24 with a spindle 25 for each package. Thisspindle is not identical in design with the correspondingly numberedspindlein the Jones patent and, as can be seen in FIGS. 6 to 8, performsan additional function.

In the Jones patent the spindle is in the center of the yarn package,which is fixed on it in normal manner. In the present invention thespindle 25 is eccentric in the large hollow center of the inner packagecore, which is numbered 28 in FIGS. 6 to 8. This construction does notshow in the plan view of FIG. 1. In order not to confuse FIG. 1, onlyone bracket 24 is shown at the right, and similarly only one bracket 26for tensioning device 10A. The brackets 24 show the spindle 25 but,again, in order to avoid confusing the drawing this reference numeral isnot repeated for each package.

It will be seen that only the tensioning device 10A is shown in sectionin FIG. 1. At this point it will be seen that yarn 11A from package 9Apasses into and out of the tensioning device 10A through grommets 19,which have smooth ceramic surfaces. The passage of the yarn through thetensioning device is more clearly shown in FIG. 2 and wil be describedin detail below. It will be seen that there are short tails 4 of theyarn extending from one of the grommets 19 in each tensioning devicewhile similar tails are, of course, extending from the tensioningdevices for the packages on the bottom or return of the chain 5. In FIG.1 only three tails are shown.

Package 98 has moved to a point so that the tail is opposite a clamp orpin on the chain 1R. This pin has been temporarily opened by the wellknown cam, as is shown in FIG. 5 of the Carman patent. It is shown onlydiagrammatically in FIG. 1. There is a vacuum funnel 3 which pulls outthe tail 4, and this is also conventional in all carousel machines andis shown only diagrammatically. As the chain 1R moves, the pin which hasreceived the tail 4 moves off its sprocket and clamps the yarn. Ofcourse, this has occurred with the tails of the preceding packages 9C to90. As a result, yarns 12C to 120 are strung between the chains as thepackages move. However, as will be described below, the yarn does notunwind from the packages throughout the whole of their travel as it doesin the Jones machine. After package 90 has moved past chain 1L and hasbeen clamped by the corresponding pin 2, which was opened and closed ashas been described above in connection with the pin 2 which clamped ontothe tail 4 on the right hand chain, a cutter 13 cuts the yarn, leaving atail, which can be seen as 4 in the yarn from the package 90, which isgetting ready to turn around the sprocket of the chain 5. Since the yarnin FIG. 1 is elastic yarn, a separate track extends beyond the cutter 13to the left of where the packages move past the carrier chain IL. Thissomewhat shorter section of cam opens the clamping discs. Upon leavingthe cam, the discs close and grip the yarn, after the slack has beentaken up. This occurs just before severing by the cutter 13, whichleaves a tail where the yarn is cut which is long enough to be suckedout by the funnel on package past the chain 1R, as has been described.If the yarn had been under tension at this point, it would havestretched and the tail would snap back into the package and so would notbe available to be clamped by the pin on chain 2R as it goes past it.The mechanism of deactivating braking is described in detail below inconjunction with the description of FIGS. 6 to 8. The operation isexactly the same inthe short extent of cam 30 to the left of chain 2L.

As in the Jones machine, a cam 14 is mounted on the frame 7 with anentrance ramp just beyond the tensioning device C and an exit ramp justbeyond the tensioning device ION. As FIG. 1 is a plan view, the gentleslope of these two ramps does not show. In addition to the cam 14, thereare shown two cam sections 30 under the packages. Their operation willbe described in more detail below. The length or lengths of the cams 30can be varied, as has been mentioned, and it will be seen they aredetachably mounted on the frame of the machine, being attachable atvarious points by bolts 33. These bolts fasten into a series of threadedholes in the frame but only two bolts are illustrated in FIG. 1 in orderto avoid confusing the figure.

FIGS. 2 to 5 illustrate the intermittent tensioning devices of the Jonesmachine, which are present also in the present invention. They willfirst be described. It will be seen in FIG. 2 that the yarn entersthrough one grommet 19, passes around guiding rolls 23 and then betweentwo discs 20. These discs are mounted on a bolt 21 and can move againstthe tension of the spring 22. This can best be seen in FIGS. 3, 4 and 5.FIG. 2 represents the position occupied by tensioning discs 10D in FIG.1 and also in the same position for tensioning devices 10E to 100. A rod15 can be seen to have been moved up by the cam 14. This rod moves in anextension 18 of the housing 10 against a spring 17 and is provided atits upper end with a wedge-shaped taper 16. The wedge shape can be seenmore clearly in FIGS. 4 and 5. As the rod is forced up by the cam 14, ithas separated the discs 20, as shown in FIG. 4, and therefore the yarnpassing between the discs is not held by friction and can run freely.This is also the case with the yarn from tensioning devices 10E to 100,inclusive. As a result, yarns 12E to 120 are somewhat loose.

When a tensioning device reaches the exit ramp, which is the case withthe tensioning device 10N, the rod 15 slides down the exit ramp 27 ofthe cam 14 under the urging of its spring 17. This is the position shownin FIG. 3 and in more detail for the discs in FIG. 5. The discs now gripthe yarn 111 and there is sufficient tension so that it is straightenedout until it is caught by the pin 2 on chain IL. The tension issufficient so that yarn UN is pulled taut, and in the case of elasticyarns, as will be described below, usually somewhat stretched. It iscaught by the clamping pin 2, and the chains 1L and IR then carry-theseyarns in strict parallelism to the knitting line of the weft-insertionknitting machine. This line is not shown in FIG. I as it is not changedby the present invention or, as a matter of fact, by the Jones patent.As has been mentioned above, yarn is cut by the cutter 13, leaving atail 4, which tail remains as package moves around to the positionoccuplied by package 9B, and the sequence of operation as far asstringing and intermittent tension is concerned is repeated as describedabove.

FIGS. 6 to 8 illustrate the new design of packages according to thepresent invention. This is quite different from the packages in theJones patent, where the package holder is centrally located and does notrotate. On the contrary, as can be seen in FIGS. 6 and 7, the spindle 25is eccentrically located. It is connected to an element 34 which turnson a shaft 29 on which a brake show 32 is mounted, which is best seen inFIG. 8. The element 34 is connected to the spindle 25 by a spring 31.When this spring is retracted, as can be seen in FIG. 6, it turns theshaft 29 and forces the brake shoe 32 into contact with the inside ofthe hollow core 28. This is the position shown in FIG. 6. In thisposition the package cannot turn, and so while in this position anelastic yarn is stretched. When the package moves on and climbs the rampon the right hand cam 30, it is raised,

and this permits the spring 31 to elongate, which turns the shaft 29 ina direction to move the brake shoe 32 out of contact with the inside ofthe hollow core 28. This is the position shown in FIG. 7. FIGS. 6 and 7are to relative scale and represent the relative height of the packagein both positions.

In FIG. 7 the yarn package can turn freely, and the stretched elasticyarn then pulls out additional yarn until the yarn is substantiallyrelaxed. As the packages move further on, they move off the exit ramp ofthe first cam section 30, which again applies the brake shoe 32, thusagain locking the packages 9E and 9F against turning, and causes theelastic yarn to stretch again. When the packages then strike thesomewhat longer cam section 30 at the left hand side, the entrance ramp35, which is diagrammatically indicated in FIG. 5, again raised thepackage, releasing the brake shoe, and thereafter the yarn unwindsfreely until the intermittent tensioning means 10I takes hold, whereuponit is pulled sufficiently taut so that it can be readily clamped by thepin 2 on chain IL. The position of the exit ramp 27 of cam 14 is shown asomewhat exaggerated distance from chain IL in order to make the drawingclearer. Depending on the particular elastic yarn which is to be strung,it may be considerably nearer to chain 1L. After the yarn is grasped bythe pin 2, it, of course, stretches because the cam 30 does not extendfurther, and after cutting would retract to a shorter length. This mightmake for too short a tail 4, and that is the reason why the track onwhich cutter 13 is located is somewhat longer than in FIG. 1 of theJones patent. Exact dimensions, of course, depend on positioning of theintermittent tensioning means and the nature of the elastic thread.

Theoretically it would be possible to have only a single cam 30.However, for smoothness of operation it is better to have two or morecams, which prevent excessive sagging while the packages are movingalong the cam profile and hence unlocked and free to rotate. The numberof sections of cam 30 can vary, and the present invention is not limitedto there being a plurality and very definitely not limited to an exactnumber or length of cam section. However, as having a plurality ofsections makes for smoother adjustment and operation, this isillustrated in FIG. 1. It will be noted as the packages climb the cams30 they are raised somewhat against the tension of the springs 31. InFIGS. 6 and 7 for clarity the amount by which a package is raised issomewhat exaggerated since the brake shoe 32 needs to move only a shortdistance to set the core 28 free to rotate. It is desirable to have thecams 30 so adjusted as to give sufficient movement to reliably lock andunlock cores but not an excessive movement. It is also, of course,necessary that there be actual contact with the package. However, theweight of the package and its core is sufficient to provide this smallamount of force.

FIGS. 9 to 11 illustrate the second variant, that is the application ofthe present invention to weft knitting. There may be weft knitting on acircular knitting machine or on a machine in which the needles are in astraight line. The circular machine operates with movement of the yarnfeeding devices in continuous motion in one direction whereas, ofcourse, if the needles are in a straight line the movement of feedingmust be an oscillatory one first in one direction and then in the other.As has been mentioned above, this variant of the invention is applicableeither to single or double knit fabrics. In each case the knitting is byone or two yarns which are not elastic. In the case of a single knit thenon-elastic yarns knit around the laid-in elastic weft whereas in doubleknit the elastic weft may be laid as a sandwich between the two layersof double knitting. Since the present invention is concerned only withthe feed of elastic yarn and not with the motion of the needlesthemselves, in order not to confuse the drawing only the feed mechanismis shown.

The drawings illustrate a yarn package with the large diameter core asin he first variant illustrated in FIGS. 1 to 8. The yarn package isnumbered 9, which is the same reference numeral given in the othervariant as, of course, the package itself is the same. As in FIGS. 1 to8, the packages of elastic yarn have large central cores, which are alsogiven the same reference numeral 28 as in the other figures.

FIG. 9 illustrates a stationary rim 52 on a circular knitting machine onwhich is mounted a chain 36 which is, therefore, stationary. The packageis moved around the periphery in synchronism with the motion of theknitting needles 51, which motion is not changed by the presentinvention, and therefore the needles are not shown in detail in ordernot to confuse the drawing. This motion is effected by a drive from apulley 53 turning in synchronism with the knitting machine drive, (notshown as it is not changed by the present invention). The pulley drivesa shaft 54 journaled in a fork on the stationary part 52. At the otherend of the shaft is a gear 55 which meshes with gear teeth on a movablerim 49 which turns around and inside the stationary rim portion 52.While the portions of the drive are shown in FIG. 10, the drive itselfis best seen in FIGS. 9 and 11. In FIG. 11 the movable element 49 isshown broken away. It extends across to the needles and drives aconventional cam which successively moves the needles up and down. Thisdrive is not changed at all in the present invention and is thereforenot shown in detail on FIGS. 9 and 11 in order not to confuce thedrawings.

The mo-vable element 49 carries a spindle or shaft 37 on which there isa pair of rollers 38 which contact the inner surface of the package form28. Within the hollow form there is a second shaft 39 carrying a pair ofrollers 40. The shaft 39 is connected to shaft 37 by two metal elements41. FIG. 10 shows the two shafts clearly but the view of FIG. 9 is aplan view at right angles to FIG. 10. The shafts 37 and 39 are shown insection rather than in elevation as in FIG. 10. However, FIG. 9 permitsshowing that the shaft 39 extends in a fork or slot 42. The shaft 39 isurged away from the shaft 37 by the spring 45.

A roller 43 is clamped to a spindle 44 by the set screws 46. This can beseen best in FIG. 10. Near the end of the spindle 44, which, as can beseen in FIG. 10, is journaled into the moving element 49, there is agear 47 locked to the spindle with a set screw 48. This gear meshes withthe stationary chain 36, as can best be seen in FIG. 9 since the chaindoes not show in FIG. 10. The spindle 44, to which roller 43 is locked,rotates as the gear 47 moves around the stationary chain 36. This alsoturns the roller 43, to which it is locked, and the roller in turn bearson the outside of the yarn package 9 causing the latter to rotate in adirection opposite to that of the spindle 44 and roller43. This isindicated by the arrows on FIG. 9. This causes elastic yarn to be paidout to the needles, as can be seen in the solid line on FIG. 9. This isthe yarn which is laid in on the needles of the conventional circularknitting machine. As the paying out is to a predetermined length, whichmay be somewhat less than the peripheral travel of the element 49 alongthe knitting needles, the elastic yarn is always paid out apredetermined length, and if it is shorter than the peripheral motion ofthe element 49 along the knitting needles 51 it can provide apredetermined small amount of stretch where this is desired. In FIG. 9only a single row of needles is shown, which would correspond to asingle knit. If there is a double knit, involving another set ofnotches, as is conventional, there may be two supply yarn packages,which is also con ventional on double knit knitting machines. If bothinlaid yarns are elastic, the second package may be the same as thefirst package shown in FIGS. 9 and 10 and the elements which causepaying out of the elastic yarn, i.e. drive of a movable element withgear and stationary chain, are repeated. They are not shown in drawingsas they would confuse the drawings unnecessarily.

The surface of the package 9 is in contact with the roller 43 and isrotated by it. As can be seen on the drawing, the spring 45 urges theshaft 39 away from the shaft 37, which is for the purpose of maintainingfirm contact with the roller 43 as the thickness of yarn in the packagechanges when it is unwound. As can be seen in FIG. 10, the roller 43carries a shoulder 50 on which the yarn package turns. This permitsturning but does not permit the package to slide down so that it is heldin contact with the roller 43 at a predetermined level. When, however, anew package has to be supplied the old package can be slid up and a newpackage slid down. At all times when the machine is operating the spring45 maintains the surface of the yarn in contact with the roller 43. Ofcourse when a new package is mounted the shaft 39 slides back in theslot 42 comprises the spring 45.

The rate at which yarn is unwound from the package 9 is determined bythe number of teeth on the gear 47 and of course by the diameter of theroller 43. This pays out a constant length of elastic yarn. For mostcircular knit fabrics it is desirable to have the elastic weft laidunder small tension, which can be varied depending on the nature of thefabric desired. This is effected by the number of teeth on the gear 47and diameter of roller 43. As can be seen rom FIG. 10, it is a verysimple matter to mount gears of different diameters and teeth numbers tochange the rate of paying out of the elastic yarn to produce the desiredamount of tension. The slower the roller 43 turns the greater thetension on the elalstic yarn because it moves around the circularknitting machine at constant speed, and if it is paid out more slowlythis results in the predetermined stretch. However, this is in no wayaffected by any nonuniformity of stretch of the elastic yarn but solelyby relative peripheral speed of the roller 43. Therefore, the tension isalways constant at the figure which is predetermined for a particularfabric. This is just as true with uncovered elastic yarns such asSpandex yarn as with covered yarns. As a matter of fact, the presentinvention presents much more advantage with uncovered yarans because, ashas been generally described above, it is possible to use othermechanisms with covered yarns. This permits various decorative patternsbecause the Spandex yarn, which may be white or dyed a desired color,does not show in the knitted fabric, whether single knit or double knit,but if the fabric is stretched the elastic weft can be seen. This kindof effeet can be very atractive and is desired in many cases for knitstretch fabrics.

The drive of the packages is very simple and quite positive and themechanism for maintaining constant contact with the roller 43 is alsovery simple and very reliable. This makes for a very economicalstructure for feeding elastic yarn in a weft knitting machine.

I claim:

1. In an elastic weft thread feeding device for warp knitting machinescomprising a first and second endless carrier with yarn clamping meansthereon for opening and closing to clamp on weft thread, a third endlesscarrier provided with a plurality of yarn packages, each package havingassociated with it and moving therewith a tensioning means which, withelastic yarn, act as gripping means for the yarn, the endless carriersbeing synchronously driven and positioned so that as a package comesadjacent to the clamping means on the first carrier the means opens,clamps the yarn from the package, and then strings out the yarn as thepackage continues to move, the tensioning or gripping means beingprovided with means for applying pressure to the yarn intermittently tohold the yarn as it is grasped by the clamping means on the firstcarrier, maintaining gripping for a short distance beyond, the pressurethen being released until the package approaches the clamping means onthe second carrier and reactuated for a short distance as the packagetransfers its yarn to said clamping means on the second carrier, theyarn being tension free during the major portion of the travel of eachpackage between carriers, the impovement which comprises means forproducing relative motion between packages having yarns that are elasticand a surface whereby the packages are rotated and yarn is unwoundtherefrom under substantially no tension, and means for intermittentlybraking the rotation of the yarn packages for sufficient periods tostring the yarn from carrier to carrier in predetermined length whenrelaxed and at a predetermined tension, cutting means for cutting theelastic yarn after the package has passed the second carrier chain, andmeans for producing relative motion between the package and the surface,the package being free to turn, whereby a predetermined amount of yarnis wound off under substantially no tension and a tail is formed fromthe package of suitable length for clamping to the first carrier chainwhen the package passes across it.

2. A weft thread feeding device according to claim 1 in which the yarnpackages are carried on hollow cores of relatively large internaldiameter, each package having within the hollow core a spindle attachedto the third endless carrier and a second shaft connected to the spindleby spring means and carrying a brake show adapted, when the spindle isin its lowest position, to turn the shaft and apply the brake shoe tothe inside of the hollow core, thereby locking the package againstrotation, and means actuated by movement of the packages for raising thepackages sufficiently to turn the shaft carrying the brake shoe to apoint at which the brake shoe no longer contacts the core and hence theyarn is free to unwind, whereby when the packages carry elastic yarn itis first stretched by the locked packages as and after clamping to thefirst carrier, then raised to unlock the packge and permit yarn tounwind freely, whereby the yarn first unwinds to the point where ittakes up the stretch and means adjacent the second endless carrier toagain lock the package core from turning, the device being provided witha cutting means beyond the second endless carrier for sufficientdistance to permit relaxation of the slightly stretched yarn to form atail of predetermined length.

3. A device according to claim 2 in which the carrier for the packagesrotates in a vertical plane, the packages extend horizontally, and themeans for raising lowering the packages are cam means attached to theknitting machine frame.

4. A device according to claim 1 in which the intermittent tensioning orgripping means for the yarn are a pair of discs spring urged againsteach other and a rod pressure on the yarn.

1. In an elastic weft thread feeding device for warp knitting machinescomprising a first and second endless carrier with yarn clamping meansthereon for opening and closing to clamp on weft thread, a third endlesscarrier provided with a plurality of yarn packages, each package havingassociated with it and moving therewith a tensioning means which, withelastic yarn, act as gripping means for the yarn, the endless carriersbeing synchronously driven and positioned so that as a package comesadjacent to the clamping means on the first carrier the means opens,clamps the yarn from the package, and then strings out the yarn as thepackage continues to move, the tensioning or gripping means beingprovided with means for applying pressure to the yarn intermittently tohold the yarn as it is grasped by the clamping means on the firstcarrier, maintaining gripping for a short distance beyond, the pressurethen being released until the package approaches the clamping means onthe second carrier and reactuated for a short distance as the packagetransfers its yarn to said clamping means on the second carrier, theyarn being tension free during the major portion of the travel of eachpackaGe between carriers, the impovement which comprises means forproducing relative motion between packages having yarns that are elasticand a surface whereby the packages are rotated and yarn is unwoundtherefrom under substantially no tension, and means for intermittentlybraking the rotation of the yarn packages for sufficient periods tostring the yarn from carrier to carrier in predetermined length whenrelaxed and at a predetermined tension, cutting means for cutting theelastic yarn after the package has passed the second carrier chain, andmeans for producing relative motion between the package and the surface,the package being free to turn, whereby a predetermined amount of yarnis wound off under substantially no tension and a tail is formed fromthe package of suitable length for clamping to the first carrier chainwhen the package passes across it.
 2. A weft thread feeding deviceaccording to claim 1 in which the yarn packages are carried on hollowcores of relatively large internal diameter, each package having withinthe hollow core a spindle attached to the third endless carrier and asecond shaft connected to the spindle by spring means and carrying abrake show adapted, when the spindle is in its lowest position, to turnthe shaft and apply the brake shoe to the inside of the hollow core,thereby locking the package against rotation, and means actuated bymovement of the packages for raising the packages sufficiently to turnthe shaft carrying the brake shoe to a point at which the brake shoe nolonger contacts the core and hence the yarn is free to unwind, wherebywhen the packages carry elastic yarn it is first stretched by the lockedpackages as and after clamping to the first carrier, then raised tounlock the packge and permit yarn to unwind freely, whereby the yarnfirst unwinds to the point where it takes up the stretch and meansadjacent the second endless carrier to again lock the package core fromturning, the device being provided with a cutting means beyond thesecond endless carrier for sufficient distance to permit relaxation ofthe slightly stretched yarn to form a tail of predetermined length.
 3. Adevice according to claim 2 in which the carrier for the packagesrotates in a vertical plane, the packages extend horizontally, and themeans for raising lowering the packages are cam means attached to theknitting machine frame.
 4. A device according to claim 1 in which theintermittent tensioning or gripping means for the yarn are a pair ofdiscs spring urged against each other and a rod with a wedge-shaped endand cam means attached to the knitting machine frame to move the rod upand cause the wedge to move the disc apart thus relieving pressure onthe yarn.
 5. A device according to claim 2 in which the intermittenttensioning or gripping means for the yarn are a pair of discs springurged against each other and a rod with a wedge-shaped end and a cammeans attached to the knitting machine frame to move the rod up andcause the wedge to move the discs apart thus relieving pressure on theyarn.